Munir Ahmed Farhad, spokesman for Shortba's governor, said the attack on the district headquarters in the northern province of Balkh started early in the morning. Zabihullah Mujahid, a spokesman for the Taliban, said "elements" had invaded the compound.
Farhad denied the allegations, saying: The Afghan security forces still control the headquarters of the province and that the reinforcements were on their way to Shortba.
Mohammad Fadl Hadid, the head of the Balkh provincial council, said the area was very remote, adding that he feared the death toll could rise further if the reinforcements did not arrive immediately.
"I hope the reinforcements will arrive sooner rather than later," he said.
Taliban attacks continued unabated even as Afghanistan held presidential elections on Saturday and US and Taliban talks on a peace deal collapsed last month, the agency said.
There were at least 68 Taliban attacks across the country during election day, mostly with rockets fired from remote locations.
Despite improved security, authorities said 431 polling stations remained closed because it was impossible to ensure their security.